diff --git a/litellm/proxy/_types.py b/litellm/proxy/_types.py
index 5ab66e4fcf..536531496f 100644
--- a/litellm/proxy/_types.py
+++ b/litellm/proxy/_types.py
@@ -2207,7 +2207,7 @@ class SpecialHeaders(enum.Enum):
     azure_authorization = "API-Key"
     anthropic_authorization = "x-api-key"
     google_ai_studio_authorization = "x-goog-api-key"
-    bing_search_authorization = "Ocp-Apim-Subscription-Key"
+    azure_apim_authorization = "Ocp-Apim-Subscription-Key"
 
 
 class LitellmDataForBackendLLMCall(TypedDict, total=False):
diff --git a/litellm/proxy/auth/user_api_key_auth.py b/litellm/proxy/auth/user_api_key_auth.py
index d3caa1194f..948e37be8a 100644
--- a/litellm/proxy/auth/user_api_key_auth.py
+++ b/litellm/proxy/auth/user_api_key_auth.py
@@ -75,10 +75,10 @@ google_ai_studio_api_key_header = APIKeyHeader(
     auto_error=False,
     description="If google ai studio client used.",
 )
-bing_search_header = APIKeyHeader(
-    name=SpecialHeaders.bing_search_authorization.value,
+azure_apim_header = APIKeyHeader(
+    name=SpecialHeaders.azure_apim_authorization.value,
     auto_error=False,
-    description="Custom header for Bing Search requests",
+    description="The default name of the subscription key header of Azure",
 )
 
 
@@ -289,7 +289,7 @@ async def _user_api_key_auth_builder(  # noqa: PLR0915
     azure_api_key_header: str,
     anthropic_api_key_header: Optional[str],
     google_ai_studio_api_key_header: Optional[str],
-    bing_search_header: Optional[str],
+    azure_apim_header: Optional[str],
     request_data: dict,
 ) -> UserAPIKeyAuth:
 
@@ -333,8 +333,8 @@ async def _user_api_key_auth_builder(  # noqa: PLR0915
             api_key = anthropic_api_key_header
         elif isinstance(google_ai_studio_api_key_header, str):
             api_key = google_ai_studio_api_key_header
-        elif isinstance(bing_search_header, str):
-            api_key = bing_search_header
+        elif isinstance(azure_apim_header, str):
+            api_key = azure_apim_header
         elif pass_through_endpoints is not None:
             for endpoint in pass_through_endpoints:
                 if endpoint.get("path", "") == route:
@@ -1160,7 +1160,7 @@ async def user_api_key_auth(
     google_ai_studio_api_key_header: Optional[str] = fastapi.Security(
         google_ai_studio_api_key_header
     ),
-    bing_search_header: Optional[str] = fastapi.Security(bing_search_header),
+    azure_apim_header: Optional[str] = fastapi.Security(azure_apim_header),
 ) -> UserAPIKeyAuth:
     """
     Parent function to authenticate user api key / jwt token.
@@ -1174,7 +1174,7 @@ async def user_api_key_auth(
         azure_api_key_header=azure_api_key_header,
         anthropic_api_key_header=anthropic_api_key_header,
         google_ai_studio_api_key_header=google_ai_studio_api_key_header,
-        bing_search_header=bing_search_header,
+        azure_apim_header=azure_apim_header,
         request_data=request_data,
     )
 
diff --git a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
index fcbdfc1fc6..e919cb1a60 100644
--- a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
+++ b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
@@ -3,7 +3,7 @@ import asyncio
 import json
 from base64 import b64encode
 from datetime import datetime
-from typing import List, Optional
+from typing import List, Optional, Union, Dict
 from urllib.parse import urlencode, parse_qs
 
 import httpx
@@ -296,6 +296,22 @@ def get_response_headers(
     return return_headers
 
 
+def get_merged_query_parameters(
+    existing_url: httpx.URL, request_query_params: Dict[str, Union[str, list]]
+) -> Dict[str, Union[str, List[str]]]:
+    # Get the existing query params from the target URL
+    existing_query_string = existing_url.query.decode("utf-8")
+    existing_query_params = parse_qs(existing_query_string)
+
+    # parse_qs returns a dict where each value is a list, so let's flatten it
+    existing_query_params = {
+        k: v[0] if len(v) == 1 else v for k, v in existing_query_params.items()
+    }
+
+    # Merge the query params, giving priority to the existing ones
+    return {**request_query_params, **existing_query_params}
+
+
 def get_endpoint_type(url: str) -> EndpointType:
     if ("generateContent") in url or ("streamGenerateContent") in url:
         return EndpointType.VERTEX_AI
@@ -328,23 +344,16 @@ async def pass_through_request(  # noqa: PLR0915
         )
 
         if merge_query_params:
-            # Get the query params from the request
-            request_query_params = dict(request.query_params)
-
-            # Get the existing query params from the target URL
-            existing_query_string = url.query.decode("utf-8")
-            existing_query_params = parse_qs(existing_query_string)
-
-            # parse_qs returns a dict where each value is a list, so let's flatten it
-            existing_query_params = {
-                k: v[0] if len(v) == 1 else v for k, v in existing_query_params.items()
-            }
-
-            # Merge the query params, giving priority to the existing ones
-            merged_query_params = {**request_query_params, **existing_query_params}
 
             # Create a new URL with the merged query params
-            url = url.copy_with(query=urlencode(merged_query_params).encode("ascii"))
+            url = url.copy_with(
+                query=urlencode(
+                    get_merged_query_parameters(
+                        existing_url=url,
+                        request_query_params=dict(request.query_params),
+                    )
+                ).encode("ascii")
+            )
 
         endpoint_type: EndpointType = get_endpoint_type(str(url))